The sinogram data of a real patient were obtained from a commercial CBCT machine (Q-FACE, HDXWILL).
The voxel size was \(1200\times 654\times 658\)  with real scale of \(0.2\)  mm for each axis, where 1200 is the number of uniformly sampled projection views in \([0,2\pi )\) , and \(654 \times 658\)  is the number of samples measured by the 2D flat detector for each projection view. CBCT images were reconstructed in a voxel size of \(800\times 800\times 400\)  with a real scale of \(0.2\) mm. For cone beam projection and back-projection (FDK reconstruction), an open-source code, TIGRE [1]}, was used after modification to make it suitable for the experimental setting.
